An isosurface is a surface that represents points of a constant value (e.g., pressure, temperature, velocity or density) within a volume of space. Isosurface extraction is an important technique widely used in visualization. For example, isosurface extraction is used in computed tomography (CT), magnetic resonance (MR), video games and for rendering terrains and surfaces. The object of isosurface extraction is to generate a polygonal mesh representing an isosurface in a three-dimensional (3D) scalar field (i.e., a volume).
Conventional techniques for extracting an isosurface include raycasting and marching cubes or tetrahedra. Although conventional techniques allow reasonably accurate isosurfaces to be extracted from 3D scalar fields, they suffer from two shortcomings. First, they are relatively slow; and second, they take inadequate advantage of modern GPU architectures.